org.springframework.web.method.annotation

Class ExpressionValueMethodArgumentResolver

java.lang.Object

org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver

org.springframework.web.method.annotation.ExpressionValueMethodArgumentResolver

All Implemented Interfaces:

HandlerMethodArgumentResolver

public class ExpressionValueMethodArgumentResolver
extends AbstractNamedValueMethodArgumentResolver

Resolves method arguments annotated with @Value.

An @Value does not have a name but gets resolved from the default value string, which may contain ${...} placeholder or Spring Expression Language #{...} expressions.

A WebDataBinder may be invoked to apply type conversion to resolved argument value.

Since:

3.1

Author:

Rossen Stoyanchev

Nested Class Summary

Nested classes/interfaces inherited from class org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver

AbstractNamedValueMethodArgumentResolver.NamedValueInfo

Constructor Summary

Constructors

Constructor and Description
ExpressionValueMethodArgumentResolver(ConfigurableBeanFactory beanFactory) Create a new ExpressionValueMethodArgumentResolver instance.

Method Summary

Modifier and Type	Method and Description
protected AbstractNamedValueMethodArgumentResolver.NamedValueInfo	createNamedValueInfo(MethodParameter parameter) Create the AbstractNamedValueMethodArgumentResolver.NamedValueInfo object for the given method parameter.
protected void	handleMissingValue(String name, MethodParameter parameter) Invoked when a named value is required, but AbstractNamedValueMethodArgumentResolver.resolveName(String, MethodParameter, NativeWebRequest) returned null and there is no default value.
protected Object	resolveName(String name, MethodParameter parameter, NativeWebRequest webRequest) Resolve the given parameter type and value name into an argument value.
boolean	supportsParameter(MethodParameter parameter) Whether the given method parameter is supported by this resolver.

Methods inherited from class org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver

handleMissingValue, handleMissingValueAfterConversion, handleResolvedValue, resolveArgument

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ExpressionValueMethodArgumentResolver

public ExpressionValueMethodArgumentResolver(@Nullable
                                             ConfigurableBeanFactory beanFactory)

Create a new ExpressionValueMethodArgumentResolver instance.

Parameters:

beanFactory - a bean factory to use for resolving ${...} placeholder and #{...} SpEL expressions in default values; or null if default values are not expected to contain expressions

Method Detail

supportsParameter

public boolean supportsParameter(MethodParameter parameter)

Description copied from interface: HandlerMethodArgumentResolver

Whether the given method parameter is supported by this resolver.

Parameters:

parameter - the method parameter to check

Returns:

true if this resolver supports the supplied parameter; false otherwise

createNamedValueInfo

protected AbstractNamedValueMethodArgumentResolver.NamedValueInfo createNamedValueInfo(MethodParameter parameter)

Description copied from class: AbstractNamedValueMethodArgumentResolver

Create the AbstractNamedValueMethodArgumentResolver.NamedValueInfo object for the given method parameter. Implementations typically retrieve the method annotation by means of MethodParameter.getParameterAnnotation(Class).

Specified by:

createNamedValueInfo in class AbstractNamedValueMethodArgumentResolver

Parameters:

parameter - the method parameter

Returns:

the named value information

resolveName

@Nullable
protected Object resolveName(String name,
                                       MethodParameter parameter,
                                       NativeWebRequest webRequest)
                                throws Exception

Description copied from class: AbstractNamedValueMethodArgumentResolver

Resolve the given parameter type and value name into an argument value.

Specified by:

resolveName in class AbstractNamedValueMethodArgumentResolver

Parameters:

name - the name of the value being resolved

parameter - the method parameter to resolve to an argument value (pre-nested in case of a Optional declaration)

webRequest - the current request

Returns:

the resolved argument (may be null)

Throws:

Exception - in case of errors

handleMissingValue

protected void handleMissingValue(String name,
                                  MethodParameter parameter)
                           throws ServletException

Description copied from class: AbstractNamedValueMethodArgumentResolver

Invoked when a named value is required, but AbstractNamedValueMethodArgumentResolver.resolveName(String, MethodParameter, NativeWebRequest) returned null and there is no default value. Subclasses typically throw an exception in this case.

Overrides:

handleMissingValue in class AbstractNamedValueMethodArgumentResolver

Parameters:

name - the name for the value

parameter - the method parameter

Throws:

ServletException